Historical ridde: Botvinnik vs. Pachman

MickyMaus90: An amazing piece of work! I am already very curious to get the PGN file...

One last addition before puting it all together in a pgn-file.

d) 34.Qxd6! Bxd6 35.Be2

Black can play the pawn sacrifice d4-d3 here as well, but White can immediately capture with a piece. This makes defending the h2 easier than in line c last time. If Black plays without d4-d3, White will slowly move his king towards d5, so Black will have to give up something or we will reach positions seen in the game/post-mortem already.

i) 35...d3 36.Bxd3 Bc5 (Now White can directly aim for the Kg4, Be8, c4 set-up.) 37.Bc4 Kg7 38.Be6 Kf6 39.Bd7 Ke7 40.Bc6 Kf7 41.Kf3 Bg1 42.c4 (Which is exactly the same position as in section c, starting with 35.Kf1 d3 36.c3!, after 45.c4.)

ii) 35...Bb4 36.Kf3 Kg7 37.Bc4 Kf6 38.Ke2 Ke7 39.Bd5 Bc3 40.Bc6 Bb4 41.Kd3 Be1 42.Kc4 Kd6 (The moment of concession. Black has to either give up the d4, permit Kc4-d5 by White, or lose the g6. 42...d3 43.Kxd3 Bf2 44.Ke2 Bg1 45.Kf3 as seen before, or 42...Bd2 43.Kd5 Bc3 44.Bb7 Kd7 45.Ba8 zugzwang 45...Ke7 46.Bc6 Kf7 47.Kd6 Kf6 48.Be8 with a set-up from the game.) 43.Be8 Bf2 44.Bxg6 Be1 45.Kd3 Ke7 46.Ke2 Bb4 47.h4 (Once more White can create a passed pawn on the kingside, because of preserving the pawnstructure with h2 and g3 all the time. The next stage is improving the pieces by king to c4 and bishop to d5. All preparations for a4-a5. Sooner are later the defenders will be overstretched. One sample line to come.) 47...gxh4 48.gxh4 Ba3 49.h5 Bc1 50.Kd3 Kd6 51.Kc4 Bh6 52.Bf7 Bd2 53.Bd5 Ke7 54.Kd3 Be1 55.h6 Kf6 56.h7 Kg7 57.Bg8 (Not the most elegant for sure, but quick.) 57...Ba5 58.Kc4 Be1 59.Kd5 Bc3 60.a5! Bxa5 61.Kxe5 +-

Although in this line Black has a new way for long-time resistance by giving up the g6, I still like 35.Be2 the most. But I guess, this is a matter of preference.

Stage three: White's king goes to the queenside to prepare a4-a5. This will quickly force a concession by Black, as his king has to help defending the queenside. White wins one of Black's doubled g-pawns. Now all White's previous efforts pay out, as the h2,g3 majority is healthy and he can create a passed h-pawn.
In several lines the engine has given up any hope for Black, showing evaluations of +10 and more. But as Black is blockading, I keep on analysing until the resistence is broken in my mind.
48.Kf3 Bg1 49.Ke2 Kg7 (49...g4 50. Kd3) 50.Kd3 Kf6 51.Kc3 g4 (51...Bf2 52.Kb3 Bg1 53.a5! bxa5 54.Ka4 Bb6 55.c5! Bxc5 56.Kxa5 +-) 52.Kb3 g5 (52... Ke7 53.Bxg6 Kd6 54.a5! bxa5 55.Ka4 Bxh2 56.b6 Bg1 57.Kxa5 Kc6 58.Be8+ Kb7 59.Kb5 Bxb6 60.c5 Bd8 61.Bd7 Bg5 62.Bxg4 Be3 63.Bh5 Bf2 64.g4 Be3 65.Kc4 Kc6 66.Be8+ Kc7 67.Kd5 Bf4 68.Ke6 +-) 53.Bd7 Ke7 54.Bxg4 Kd6 55.h4 gxh4 56.gxh4 Kc5 57.h5 Be3 58.Be6 Kd6 59.Bd5 Kc5 60.Kc2 Bh6 61.Kd3 Bc1 62.Ke2 Kd6 63.a5 bxa5 64.b6 a4 65.c5+ +-

c) 34.Qxd6 Bxd6 35.Kf1 d3 36.c3!

Finally the winning method. White passes by to pick up Black's d-pawn with a piece later. White's c-pawn is more valuable than the d3 in section a, after 36.cxd3. But the most important difference is the kingside. Now White will be able (and he has to) to preserve his pawns on h2,g3. The win consists out of three stages.

Stage one: Winning Black's d-pawn, but defending the h2. Whenever Black's bishop will show up on g1, White uses two tricks. The first is to answer Bg1xh2 by Ke2-f2, which catches the bishop. The second is to use the breakthrough on the queenside, that is the sequence Bg1xh2, a4-a5 b6xa5, b5-b6.
36...Bc5 37.Be6 Kg7 (37...Kh5 38.Bc4 d2 39.Bb3 Kg4 40.Kg2 Kh5 41.Kf3 Bg1 42.Ke2) 38.Bc4 d2 39. Ke2 Bg1 (39...Kf6 40. Kxd2 Ke7 41. Ke2 Kd6?! 42.Bf7, or 39...Be3 40.Bb3 Bg1 41.Kxd2) 40.Kxd2 Kf6 (40... Bxh2?! 41.a5 bxa5 42.b6 Bg1 43.b7 Ba7 44.Kc2 Kf6 45.Kb3 Ke7 46.Ka4 Kd6 47.Kxa5 Kc7 48.Ka6 Bf2 49.g4! Kb8 50.Bf7 Be1 51.c4 Bf2 52.Bxg6 Kc7 53.Bf7 Kb8 54.Bd5 Kc7 55.Kb5 Be3 56.c5 Bd4 57.Bc6 Be3 58.Kc4 Bc1 59.Kd5 Bf4 60.Ke6 Bg3 61.Bd5 Bh2 62.c6 Bg3 63.b8=Q+ Kxb8 64.Kd7 +-) 41.Ke2

Stage two: Improving the position. King to g4, bishop to e8, c-pawn to c4. This eventually safeguards White's pawn on h2.
41...Ke7 42.Kf3 Kf6 43.Bd5 Ke7 44.Bc6 Kf7 45.c4 Ke7 46.Kg4 Kf6 (46... Be3 47. c5!, or 46...Bxh2 47.c5 bxc5 48.b6 Kd6 49.Bd5 c4 50.a5 Bg1 51.Bxc4 Be3 52.Bd5 Kd7 53.Kf3 Bg1 54.g4 Bd4 55.Ke2 +-) 47.Be8 Bc5

- to be continued -

MickyMaus90: OK very good! Many thanks!

Karsten: Thank you! Yes, I will send a pgn-file to CB. But I will need a day or two. For the moment my analysis file is unreadable. With lots of duplicates, unnecessary lines and missing text.

MickyMaus90: Really great, many thanks! Zugzwang is indeed the sharpest endgame weapon.
Can you send a PGN file with your final conclusions to info et chessbase.com ?

b) 34.Qxd6 Bxd6 35.Kf3 d3 36.Ke3?
White refuses Black's pawn sacrifice, but his king will make it to d5. Which is what he failed to do in line a). It is a really close try and the most intersting line in my mind.
36...dxc2 37.Kd2 Kg7 38.Kxc2 Bb4 39.Kb3 Ba5 40.Kc4 Kf6 41.Kd5 Bc3 42.Kc6 Ba5 (This very much resembles the game, respectively the post-mortem. The difference is the missing pawn pair c2/d4.) 43.Bd7 (The bishop goes to e8 for the g6 again. The other idea is to infiltrate from the back side. 43.Kd7 Kf7 44.Be6+ Kf6 45.Bc4 Bb4 46.Ke8 Be1? 47.Kf8! Bb4+ 48.Kg8! Bc5 49.g4 Bb4 50.Bf7 Bd2 51.Be8 Bb4 52.Kh7 Bc3 53.Bxg6+- and so on. But this is all in vain as 46...Kg7! holds.) 43...Ke7 44.Kc7 Kf7 45.Kd8 Bc3 46.Be8+ Kf6 47.Kc7 Ba5 (Soon White will try what we have seen before, a bishop sac in g6. Before that he has to decide on the setup of his kingside pawns. The most effective seems to be g3,h3.) 48.h3 (The reason is this 48.Kc6 Kg7! 49.Kd6 Kf6 50.Bxg6?! Kxg6 51.Kxe5 Bc3+ 52.Ke6 g4!=) 48...Kg7! 49.Kd6 Kf6! 50.Bxg6 Kxg6! 51.Kxe5 Be1! 52.Ke6 Bxg3 53.e5 Kg7! 54.Kd6 Kg6! 55.Kc6 Bxe5! 56.Kxb6 (Looks promising to a human maybe, but we are already in TB land.) 56...Kh5! 57.a5 Kh4! 58.a6 Kxh3! 59.Kc5 g4! 60.a7 g3! 61.a8Q g2! (Somewhat unlucky that this is a non-win for White, but he can try something practically.) 62.Qc8+ Kh2! 63.Kd5 g1Q! 64.Qc2+ Kh3! 65.Qf5+ Kg2! 66.Qxe5 (Queen and knight pawn vs queen. A theoretical drawn position. The defending king is already in the right corner. But it is similar to Botvinnik-Minev, Amsterdam 54, which Botvinnik won.)

Karsten: 34.Qxd6 Bxd6 35.Kf1 d3 36.cxd3 Kg7 37.d4 exd4 38.Ke2
Actually I relied on the fact that White got a passed e-pawn in addition to the motif a4-a5 and that the evaluation of SF14 goes quickly beyond +5. Looking a bit deeper now it is 38...Kf6 39.Kd3 Ke5 40.Bd7 Bc5 41.Bc6 Ke6 42.Bd5+ Kf6 43.Bb3 Ke5 44.Bf7 Kf6 45.Be8 and in this key position Black is in zugzwang. He has to give up the g6, the d4 or after 45...g4 46.Bd7 the g4. Or finally give way by 45...Kg7 46.e5 +-.
After the immediate 41.Be8 (instead of 41.Bc6) 41...Kf6 White has no good move and he has to regroup. Losing a tempo is the reason for White's somewhat strange maneuvering with the bishop.

MickyMaus90: Many thanks! Deep stuff! Can you give more details on "(36...Kg7? 37.d4! exd4 38.Ke2, the resac of White in this form must be prevented.)" ? How does White win ?

a) 35.Kf1 d3 (This is Black's only chance, as otherwise White can play Kf1-e2-d3-c4 and win as has been shown here in previous good comments to the game. White improves to the maximum and plays for a bishop sacrifice on g6.) 36.cxd3? (For one, White's pawn d3 is an obstacle for his king on the way to d5, so Black gains some valuable time. But the most important point is that the diagonal c5-g1 is now open for Black's bishop. A few moves later, we will see the effect.) 36...Bc5! (36...Kg7? 37.d4! exd4 38.Ke2, the resac of White in this form must be prevented.) 37.Ke2 (37.d4 Bxd4 38.Ke2 Bg1=) 37...Bd4! (37...Kg7?! allows 38.d4 Bxd4 39.Kd3 Kf6 40.Kc4, which will see in section b later.) 38.Bd7 (Placing the bishop on e8 first to get pressure on g6. If instead White rushes over with the king at once, Black's king will be in time. 38.Kd1 Kg7! 39.Kc2 Kf6 40.Kb3 Ke7! 41.Kc4 Kd6! 42.Bc8 and now Black can simplify his task with the trick 42...g4!? 43.Bxg4 Bg1 44.h3 Bf2 45.Bc8 Bxg3=) 38...Kg7 39.Be8 Kf6 40.Kd1 Bg1! (A key move. White's kingside pawns must be pushed away from the black squares h2,g3 to h3,g4.) 41.h3 Bf2! 42.g4 Be3 43.Kc2 Bd4 44.Kb3 Be3 45.Kc4 Ke6! (White must not be allowed to play Kc4-d5. So Black loses a third pawn.) 46.Bxg6 Kd6 (All three white majorities are poor, because of the backward pawns on white squares each time. With his pawns still on h2 and g3 White would win now, as he could create a passed h-pawn by h2-h4. That is why Bc5-g1-f2 was necessary. Which in turn was only possible by clearing the diagonal c5-g1 with d4-d3 in move 35. In my mind it is too early to call the resulting position a positional draw. Because with his three extra pawns, White has many chances to play for some resacs. But I don't see any setup for White to succeed. One example for illustration to come, but it is unforced and Black has alternatives.) 47.Bf5 Bf2 48.d4 Bxd4 49.h4 gxh4 50.g5 Be3 51.g6 Bh6 52.Kb4 Bd2+ 53.Kb3 Ke7! 54.Kc4 Kf6 55.Kd5 Bc3 56.Kc6 Ba5=

To the ending after 34.Qxd6 Bxd6. I think I divide it into three sections.
a) the idea of Black's d4-d3, that is White plays c2xd3
b) White tries to hurry over to the queenside with his king, that is Black can play d3xc2
c) White passes by with c2-c3

MickyMaus90: OK very good. It now basically agrees with the planned solution by Charles Sullivan and Zoran Petronijevic. More details are welcome of course.

Karsten: Thanks for confirming. So for now it is
32.Qd5 Kh6 (or 32...d3, both are ok) 33.Bg4 Qd6? (33...d3! holds) 34.Kf3? (34.Qxd6! wins) 34...Kg7? (either 34...Qf6+ 35.Kg2 d3! or 34...Qf8+ 35.Kg2 d3! hold) 35.Qxd6! etc +-

Zoranp: Yes, after 34.Qxd6 Bxd6 White can win by 35.Kf3 d3 36.c3!, I agree. Play will quickly come to the same as after 35.Kf1 d3 36.c3!.
My main point was, that after Black's pawn sac (by d4-d3) neither accepting (by c2xd3), nor ignoring (by letting Black play d3xc2 and moving the white king to d2) is any good. The right way is to pass by with c2-c3. Sorry, for being a bit unclear about that.

Actually, White has three more winning moves (after 34.Qxd6 Bxd6). 35.Kf2 d3 36.c3 and 35.Be6 d3 36.c3 are offering nothing new. But 35.Be2 might be the most principled, although Black can still try 35...d3 36.Bxd3 Bc5.

Later I will try to give more details and ideas on the ending after 34.Qxd6 Bxd6 from my point of view.

I mainly agree with MickyMaus90's analysis, except in one: 34.Qxd6 Bxd6 move 35. Kf1 suggested by You is winning. However, move 35.Kf3 rejected by You, in my opinion, wins as well: 35...d3 and now not 35.Ke3, which is a draw, but 35.c3! which should win: 35...Bc5 36.Be6 Kg7 36.Bc4 d2 37.Ke2 Kf6 38.Kd2 and this position is winning for White.

MickyMaus90: Indeed 34.Qxd6 should be winning for White so more questions arise...

MickyMaus90: Many thanks! 32...d3 33.Qxd3 Qf2+ 34.Kh3 is also given by Botvinnik and indeed most probably draws.

The difficulty of the position is that the pure opposite-coloured bishop ending can arise in several, slightly different constellations.
As the version of the game after 34...Kg7? is lost for Black, the first (natural) try is to keep the queens on board and play for active defence, I suppose. Black had three chances to do so, in the moves 32 to 34.
First by 32...d3 33.Qxd3 Qf2+ 34.Kh3. Here White's two extra pawns are backward and of no immediate effect. He can make a little progress by handing over the control of f1 from the queen to the bishop. In some situations Black must react very precisely. But overall it seems White can't succeed. A sample line, containing a lot of White's probing:
34...Kh6 35.Bg4 Kg7 36.Be2 (36.Qe2 Qd4) 36...Be7 (not 36... Kh6? 37.Qf3 Qd4 38.Qf6) 37.Qf3 (37. Qd7 Qxe2 38.Qxe7+ Kh6 39.Qf8+ Kh7 40.c3 Qg4+ 41.Kg2 Qe2+ 42.Qf2 Qxe4+ 43.Qf3 Qc2+ 44.Kh3 e4=) 37... Qd4 38.Qg4 Qf2 39.Bd3 Bf6! 40.Qe6 Kh6! 41.Qd7 Qg1 42.Qc8 Kg7 43. Qe6 Qf2! 44.Bc4 Kh6! 45.Bd3 (45.Qf7?! g4+! 46.Kxg4 Qxh2 47.Kf3 Qh1+=) 45...Kg7 46.Qg4 Kh6 47.Qe2 Qg1! 48.Kg4 Kg7 49.Bc4 Kh6 50.Qd2 Qh1 51.Bd3 Qg1 52.Qe2 Kg7 53.Kh3 Kh6 (Black can avoid the following transition by 53... Be7. But as White could do it before and possibly force it anyway, let's see.) 54.Qf1!? g4+ 55.Kxg4 Qxh2 56.Qh3+ Qxh3+ 57.Kxh3 Be7 58.a5 bxa5 59.b6 a4! 60.Kg4 a3 61.Bc4 Bc5 62.b7 Bd6 and Black holds.

The even bigger question is, what happens if White exchanges the queens one move earlier, so 34.Qxd6 Bxd6. To avoid the fate of the game, Black has to throw in d4-d3 in the next move. It seems White wins after 35.Kf1 d3 36.c3!, then picking up the d3 with a piece and setting up for both pawn-breacks a4-a5 and c4-c5. Neither 35.Kf3 d3 36.Ke3 dxc2 37.Kd2, nor 35.Kf1/f3 d3 36.cxd3 seem to win. But for now I don't have the details.

Wolfram Schön, Bergisch Gladbach

Peter B: Yes indeed. This win was proved by Botvinnik.

I think after 42... Ba5 first 43 Kc7 Kg7 and only now 44 Kd6. Then black has choice of 44... Bc3 45 Ke6 and eventually winning the pawn on either e5 or g6 (Black bishop cannot move: 45 ... Bb2 46 a5!) or 44... Kf6 45 Bxg6 Kxg6 46 Kxe5 Bc3 47 Ke6 which I assume wins

You're right Bert, with half an eye on the board and for the rest looking at things I'm supposed to do, I thought there was something with a4-a5 there – but that's nonsense.

Hi Frits, one small problem: on Kd5 the black Bishop goes to c3, effectively protecting e5; see 42. Kc6 Ba5 43.Kd5 Bc3 44. Bxg6 Kxg6 45.Kxe5 d3 and the black pawn promotes.

Hi Bert, you've got to sacrifice the bishop on g6. Then there are no more opposite coloured bishops... My engine is older than our car, so I won't join in the contest, but that's the way to go in a game.

Quite frankly, I don't see the win in the final position! Black can play 42. ... Ba5 and there is no zugzwang, since the black King can move between f6 and g7 and if the white King get closer, the Bishop is free to move.